The present invention relates to a video signal recording apparatus for an electronic camera (or a digital still video camera), and more particularly to a video signal recording apparatus capable of recording an input video signal generated from a second video signal source without regard to input equipment.
Generally, an electronic camera is designed to photograph and record the image of an object by photoelectrically converting it with a charge-coupled device (CCD). Recently, an electronic camera was developed which digitizes a photographed video signal to write it into a detachable memory card composed of integrated circuits. Such an electronic camera is illustrated in FIG. 1.
When a user sets a photograph/write mode, a system controller 50 supplies a control signal to a synchronous signal generator 60. Synchronous signal generator 60 generates vertical and horizontal synchronizing signals according to a clock signal output from system controller 50 and simultaneously supplies them to a first video signal source 10 and a buffer memory 30. First video source 10 is controlled by the synchronous signals to convert the image of an object into an analog video signal. In other words, first video source 10 consists of a lens, a diaphragm, a color filter and a CCD, wherein the object's image is formed on the CCD via the lens, diaphragm and color filter. The image is then photoelectrically converted and output by the CCD. A video signal output from first video signal source 10 is converted into a digital signal by an analog-to-digital (A/D) converter 20 to be applied to a buffer memory 30. Being controlled by a control signal of system controller 50 input via a first interface 70 and a synchronous signal of synchronous signal generator 60, buffer memory 30 temporarily stores applied video signals by frames. A video signal output from buffer memory 30 is controlled by a control signal of system controller 50 input via a second interface 80 to be written into a predetermined region of a memory card 40. Here, if there is no room to write video signals on memory card 40 or the memory card is not installed, buffer memory 30 stores at least one frame of the video signal, and interrupts the pickup of the next image.
However, the conventional electronic camera can store only analog video signals input via the CCD used in first video signal source 10. That is, since the synchronous signal generated from synchronous signal generator 60 doesn't match the synchronous signal of the video signal output from an external video signal source (for example, from a video tape recorder, a video camera, etc.), proper storage is impossible.